年別アーカイブ: 2017年

Speaker1
Tadafumi Matsuno, SOKENDAI 3rd year (D1)(Supervisor: Wako Aoki,Takuji Tsujimoto,Yutaka Komiyama)
Title
Chemically-old stars with young age estimates
Abstract
The combination of a large spectroscopic survey and asteroseismology has discovered a peculiar stellar population in the Galactic disk: they are estimated to be young from their masses but has similar alpha-elements abundances to old stars. Since their existence is not predicted in simple galactic chemical evolution models, the origin is yet to be explained. We obtained high-quality high-resolution optical spectra for 14 of such stars. In addition to the confirmation of their alpha-enhancements, we show that they follow the typical abundance pattern of old stars in almost all the measured elements. Together with the high frequency of radial velocity variation, we suggest they are results of stellar merger or mass transfer from red giants.

Speaker2
Takafumi Tsukui, SOKENDAI 1st year (M1)(Supervisor: 井口聖,永井洋,松田有一)
Title
電波銀河の形成過程の解明
Abstract
Please note that the presenter information posted here is not necessarily listed in order of presentation.

[Speaker3]
Satoshi Kikuta, SOKENDAI 3rd year (D1)(Supervisor: Masatoshi Imanishi,Yuichi Matsuda,Yutaka Komiyama)
[Title]
Lyman Alpha Imaging around a Hyperluminous QSO at z=2.84
[Abstract]
Ly-alpha imaging is a powerful technique to study galaxy formation at high-redshift by detecting redshifted Ly-alpha emission line with narrowband filters. I present the latest results of our Ly-alpha imaging around a hyperluminous QSO at z=2.84, namely HS1549+1919, with HSC/Subaru. We have detected >3400 LAEs within 36 arcmin from the QSO (i.e., ~1.1 deg^2 FoV). The QSO is found to reside in the center of massive overdensity of LAEs which is embedded within a large scale (~100 cMpc) structure of LAEs. We have also detected a gigantic Ly-alpha nebula around the QSO as well as many Ly-alpha blobs. The nebula is the largest and the most luminous to date and has a peculiar morphology: bubble-like structure extending several hundred kpc. After sharing the current status I present our future plans to further reveal galaxy formation in this rich environment. Your comments and suggestions are very welcome.

[Speaker 1]
Kotomi Taniguchi, SOKENDAI 5th year (D3)(Supervisor: Masao Saito)
[Title]
Chemistry of Cyanopolyynes in the G28.28-0.36 Hot Core
[Abstract]
We carried out observations of long cyanopolyynes (HC5N and HC7N) using the Nobeyama 45 m radio telescope, the Green Bank 100 m telescope, and the Very Large Array. Long cyanopolyynes have been thought to be deficient in hot cores, around the massive young stellar objects, so far. However, we found out that the G28.28-0.36 hot core is rich in long cyanopolyynes, suggesting the chemical diversity at the hot core stage. These are the first observational results showing that cyanopolyynes are formed in hot cores.